Resistor



y 30, M. E. VANSICKLE 1,722,511

RESISTOR Filed Feb. 23 1927 l/VV/INTOR.

0 A-TTORNLY Patented July 30.1929.

UNITED STATES 1,722,511 PATENT OFFICE. 1

E. VAN F NEWARK, NEW JERSEY, ASSIGNOB T0 BBAN'DES LABOBA-' TOBIES, 1110., OF NEWARK, NEW A CORPORATION OI NEW JERSEY.

RESISTOR.

Application filed February 23, 1927. Seria1 No. 170,335.

My invention relates broadly to electrical resistors and more particularly to the construction of an electrical resistor unit in which the resistance value of the unit may be accurately fixed.

One of the objects of my invention is to provide a construction of a resistor where the resistance value may be accurately set for the manufacture and production on a large 10 scale of resistors having uniform characteristics.

Another object of my invention is to provide a construction of an electrical resistor wherein a resistance element is mounted within an insulated tube in such manner that the effective length of the resistor may be accurately selected before the resistor is sealed within theinsulated tube.

Another object of my invention is to pro- 29 vide a construction of'supporting member for each end of the resistance element within an electrical resistor where the position of the resistance element with respect to the supporting members may be readily-changed for accurately fixing the effective value of the resistance element prior to the sealing of the element within an insulated container."

My invention will be more clearly understood from the specification hereinafter 01- 30 lowing by reference to the accompanying drawings, in which:

Figure 1 is a perspective view illustrating the electrical resistor of my invention; Fig.

2 is a longitudinal cross-sectional view taken through the electrical resistorof my inven 'tion; Fig. 3 is a view representing the system which I employ for accurately setting the eflective value of the resistance element between the end supports; Fig. 4 is an en- 40 larged perspective view of one of the end supporting members employed in the resistor construction of my invention; Fig. 5 is a perspective view of a modified construction of end supporting member employed in the resistor of my invention; and Fig. 6 is a fragmentaryperspective view of a modified construction of end supporting member for the resistor of my invention showing the means which I employ for spacing the resistance element from the walls of an enclosing tube. 7

My invention is directed to a construction of a resistance element designed especiallyfor grid leaks, and chokes for resistance 5 coupled electron tube amplifiers. Electrical resistors employed as grid leaks or coupling units must have effective values of resistance within certain prescribed limits in order to obtain efiicient operation of the electron tube circuits with which the resistor is associated. In the event that the resistance value does not come within the required limits, the unit has to be taken apart and re-assembled to give the required effective resistance. The efiective resistance of the unit is determined by the length of the conducting member from one end support to an opposite end support. It has been usual to anchor the opposite ends of the electrical resistance element directlyin solder or other metallic alloy having a low melting point. Such mounting requires the re-heating of the assembled unit in order to release the resistance element for remounting at the required effective resistance value. By the construction of a resistor as described herein, I provide means for mounting the resistance element slidably between two supporting members which may be embedded in masses of solder or metallic alloy at opposite ends of a tubular container. The mountings for each end of the resistance element are so arranged that the effective value of the resistance element across the shortest distance between terminals may be changed by sliding the supporting members with respect'to the resistance element for securing that distance between the terminals which will give the desired effective resistance across the shortest distance between terminals for the resistor. Various constructions of supporting members may be provided for the ends of the resistance element. 'In some of the forms of supporting members which I employ, spacing means are integrally connected with the supporting element for centering the resistance element with respect to the insulated tubular container for the resistor. The resistance element which I employ is preferably of the type in which an insulated 109 rod or tube normally of glass is provided with a resistance coating constituting the resistance element. The ends of the rod or tube slide within pressed guideways provided for the purpose in the supporting 1 members at opposite ends of the resistor.-

Referring to the drawings in more detail, reference character 1 designates the tubular container in which the resistance element is mounted. The container 1 is provided #110 with conductive end caps 2 and 3 which. provide terminals for opposite ends of the resistance element 4. In Fig. 2, I have shown the assembly of the resistor wherein supporting members? and are provided for opposite ends of the resistance element of conducting filament 4. These supporting members 7 and 8 are anchored within the end caps 2 and 3. In previous constructions where the resistance element is anchored directly in solder and metallic alloy, the effective resistance of the unit is determined by the length of the conducting filament from solder to solder and such effective resistance can not be changed unless heat is applied to the resistor for remounting the solder and allowing the change in position of the resistance element. members 7 and 8 which clip over the ends of ,the resistance element 4 in my construction are longitudinally movable with respect to the resistance element 4. For this purpose pressed portions 10 are provided in the jaws 9 permitting the .rod or resistance element at to slide longitudinally therein. The jaws are provided with a U shaped connecting portion 11 for obtaining the required resilient properties for gripping the end of the resistance element and also provide means by which the element may be anchored within the metallic alloy or solder in the end of the tube. In Fig. 3 I have illustrated diagrammatically a Wheatstone bridge by which the efiective value of the resistance 4 may be determined and the resistance included between the shortest distance separating opposite terminals accurately set by the longitudinal movement of the end supports 7 and 8 with respect to the resistance element 4. In Fig. 5 I have shown a modified construction of clip illustrated by reference character 12 as having V shaped walls terminating at edges 14 and provided with out struck portions 15 by which the sides of the resistance element 4 may be slidably clipped.

In Fig. 6 I have shown a construction of a supporting member for the end of the resistance element which also provides means for spacing the resistor from the interior walls of the tube 1. The construction which permits of this arrangement, consists of extended strips 17 which are bent baclr atld from the jaws 9 and tend to spring against the inner walls of the tube 1 for positioning the resistor within the tube. The solder or metallic alloy surrounds and embeds the metallic parts of the supportmg member while allowing free longitudinal movement of the resistor element 4.

Where it is desired to change the resistance of the element in order that quantities of resistance may have the same uniform characteristic, it is only necessary to set the end clips at proper selected positions by The supporting .efilective length of said resistance member the arrangement represented in Fig 3 prior to the anchoring of the resistance wlthin the tube. When the properresistance value has been selected, the unit may be sealed at the predetermined resistance with the end caps "0 soldered to the end clip within the tube. VVhileI have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my mvent-ion are intended other than are imposed by the scope of the appended claims. What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. An electrical resistor comprismg a resistance member, an insulated tube enclosing-said member, supporting means located adjacent opposite ends of said tube for providing a mounting for said resistance member centrally of said insulated tube, said supporting means slidably gripping said resistance member adjacent opposite ends of said resistance member for selectively fixing the as measured across the shortest distance between said supporting members.

2. An electrical resistor comprising a tubular member, a resistance member, a pair of supporting elements each resiliently gripping the inner walls of said tubular member for slidably engaging said resistance member at points adjacent the opposite ends thereof and an enclosing tubular member in which sa d resistance member is centrally located, said resistance member being slidably mounted in said supporting members for varying the efiective resistance as measured across the shortest distance between the said supporting members.

3. A resistor comprising a resistance element, a tubular envelope enclosing said element and a spring member adapted to slldably. grip said resistance element adjacent opposite ends thereof and embrace the inner walls of said envelope for suspending said element centrally within said en velope from each end thereof while permitting limited longitudinal movement of said resistance element with respect to said spring members.

4. A resistor comprising a resistance element, a tubular envelope enclosing said resistance element, a spring jaw device arranged to slidably engage said resistance element, at points adjacent opposite ends thereof and substantially free of abutment with the projecting ends of said resistance element, said spring jaw devices being ar- 25 ranged to be moved toward or away from each other for fixing the effective resistance of said resistance velement as measured between said springjaw devices, said spring jaw devices embracing the inner walls of said tubular envelope for mounting said resistance element centrally within said envelope when, set in a selected position therein. 5. A resistor comprising a resistance element, a tubular envelope enclosin said resistance element, a spring jaw evice arranged to slidably engage said resistance element at points adjacent the opposite ends thereof, said spring jaw devices being arranged to be moved toward or away from each other for fixing the efiective resistance of said resistance element as measured between said spring jaw devices, said sprin jaw devices each having a resilient centrai portion and a pair of arms disposed parallel to the axis of said resistance element for frictionally engaging. the interior walls of said envelope an supporting the resistance element centrally within said tubular envelope.

6. An lectrical resistor comprising an insulated tubular casing, a spring strip device dis in each end of said casing, said spring strip device being bent upon itself to provide parallel exten ing arms embracing the interior walls of said casing, with an intermediate pair of arms positioned centrally of said casing, a longitudinally extending resistance member, said resistance member having its opposite ends slidably mounted between the intermediate pair of arms, whereby the effective distance between said. spring strip devices along said resistance member may be selectively fixed.

In testimony whereof I aflix m si nature.

- MELVIN E. VAN 10 E. 

